Method of making mobile starch powders



Patented Oct. 21, 1952 METHOD OF MAKING MOBILE STARCH 'POWDERS 1 George A. Krisan, Riverside, Ill. Q 7

No Drawing. Application September 14, 1949, Serial No. 115,765

. 1 This invention relates to a new and improved type of dusting powder. to dusting powders made from various starches and to methods of preparation thereof.

A satisfactory dusting powder should be a high Furthermore,

1y mobile free flowing powder. the individual particles of the powder should not stick or clump together, as this will prevent proper dispersion of the powder into its individual particles when it is dusted. This latter property is a necessary requirement if a fine uniform coating is to be obtained on the material being dusted.

Powdered starches have been used for many yearsas dusting powders because they are nonharmful in such applications where they may. come in contact with food products and because they do not present an industrial hazard to workmen who may inhale the dust. starches, however, have certain drawbacks which maketheir use for dusting purposes not entirely satisfactory.

The primary shortcomingof starch powdersas used for this purposeis the fact that they are.

somewhat hygroscopic and will pick up moisture from the air. Under average humidity conditions starches will thus reach an equilibrium moisture content which may vary from 12% to 18% depending on the variety of starch and humidity conditions encountered. At. these moisture contents starch powders are not free flowing or mobile. The starch granules tend; to clump together and do not readily disperse into the individual granules when dusted. For this reason it has been the usual practice to use for dusting purposes redried starches wherein the moisture content has been reduced to about 5%. With such reduced moisture content starch powders have better mobility and dispersing proper.- ties, and can be used with a better degreeof satisfaction. The use of such redried starch powders, however, involves storage of the starch under conditions where it cannot come in contact with air of normal humidity content and, furthermore it may be exposed to air for only .a

short period of time as it is used. If exposed for longer than a short period the moisture pickup from the air soon causes it to lose the necessary free flowing and dispersing properties. Attempts have been made to overcome these disadvantages of starch dusting powders by blending small amounts of finely powdered materials, such .as talc, mica, di-calcium phopshate, magnesium carbonate and various other material. Although such additions slightly improve the mobility and dispersing properties of the starch the results in this respect still leave much to. be desired,

It particularly relates.

It is an object of this invention to overcome the difficulties encountered with the previous starch powders as used for dustingpurposes, by providing a new and improved starch base dusting powder which has superior free flowing and mobility properities which are not adversely affected by the highest humidity conditions likelytobe encountered. The product of this invention is unique in that although like previously used dusting powders it Will pick up moisturefrom the air, such moisture will not cause it to lose its free flowing and dispersing properties. The need for special storage and handling conditions is therefore eliminated.

A further object of this invention is to provide a starch base dusting powder with a greater mobility and superior dispersing properties as compared to the redried starches previously used for this purpose.

Another object of this invention is to provide a starch base dusting powder which may be readily manufactured with available materials and which is relatively low in cost.

Another object of this invention is to provide a starch base dusting powder which is not only superior for general dusting purposes but which is particularlysuitable for the prevention of olfsetting in the printing trade. The improved mobility and free flowing properties of the product of this invention and its superior dispersing quality make it very valuable for this purpose.

The improved dusting product of this invention consists primarily of starch so treated as to uniformly envelop the individual starch granules with athin layer .of non-hygroscopic material.

To accomplish this result it is necessary for the enveloping material to consist of particles considerably smaller in size than the granules of starch. The means utilized in this invention for obtaining enveloping materials in sufliciently small particle form is the use of freshly prepared precipitates as formed by the reaction of two or more chemicals which inaqueous solution react to form an insoluble compound.

To produce the product of the invention the aqueous suspension of precipitated material is thoroughly mixed with the starch and the resultant mixture then dried and ground to a fine powder. A preferred alternate method of preparing the product of this invention is to precipitate the enveloping material in the presence of the starch rather than in a separate operation. Although the exact mechanism ofthis action is not understood, it seems probable that the small particles of freshly precipitated material surtreatment.- of" theistarch*-s-insofar as; itseffect. in:

improving the mobility and dispersing" properties of the starch is very striking.

The invention is further illustrated but is not: limited by the following examples. which.illus.-

trate its practice and the limiting factors iii-r volved. In these specific examples the quanti ties stated are parts by weight unlessmtherwisez.

stated.

Example I To 450 parts of potato starch dispersedin.1000 parts water was added 9 parts of aluminum sulfate dissolved in 40 parts of water- The mixture was agitated for aboutl'minutes, th*en 1'0 parts tri sodiumphosphate dissolved. in 40 parts of i water was addedi The agitation was continued".

for. about. minutes afterwhich the. bulk of the water: wasl's'eparate'd" from the starchby fil tration". The resultant damp starch product:

was then dried toiabout'. moisture; content. and ground to a fine powder.

This powder. is the product: of' the invention:

and differs" from the originall untreated starch. material very markedly in its highly mobilev character and its ready. di'spersability.

The proportions" of" chemicals usedli'n. this. ex;- ample are approximate and are based" on .the'fol lowing equation;

This example illustrates good practice in-the application of the invention in makings; highly satisfactory dusting product; Although a' larger" proportion of" the" chemicals to" starch. may? be" used than the proportions: specified-J in the-ex ample (about 412% by weight ofthe' starch) without" detriment to the" mobility and dispersing properties of the final product;. the use offsuch'. larger proportions does not improve the mobilityordispersing properties of the final product:

The order in' which thechemical'saraadded" to aqueous starch' suspension is' not critical" and they do not necessarily'have'to be in the form of solutions" at the time of" addition: When the chemicals are added to' the aqueous: starch" sus-'- pension in dry form it is-diflicult to determine" when complete solution and reaction; with each other have taken place; For" this reason it is usually desirable to add the chemicals inthe form of solutions.

Example II.

The procedure. followed in. this example. was

the same. as. that. followed'in ExampleI except. that the proportions of chemicals.tostarcliwere reduced. In thisexample only 0.9' part of aluminum sulfate. and .110 part of tri-sodium vphosphate were used to 450T'parts of'potato starch. The final'product obtained in this. example. was. equivalentv to that. of. Example. I. and represents.v good practice in. the. application ofv the invention.

ExampleiIII" The procedurein thisexample was the-same as-that followe'd in Example- I; exceptthat a still"- furtherreduction-inthe proportion of chemicals.

' Suits.

Example IV This example illustrates a method of preparing the: productof: theinvention wherein a lesser amount of water is used than in the previous examples 45'0part's'of potato starch was placed in a mixing device,,of the type suitable for mixing dry, orsemi-di'y, materials, and agitated; The starch used in thisinstance contained about l6'% moiseture. As the starch= was agitated 4551 parts of aluminum sulfate-dissolved in 1'00 parts-of water" was slowly added to the-starch;- After thealumi'num sulfate solution was thoroughly'mixed with the starch, 5 parts of tri-sodium phosphatedissolved in'100parts of" water was added andagit'ation continued until it" also was uniformly? dispersed throughout the starch mixture: The:

resultant damp starch mixture was then" dried to about" 15%- moisture content and ground to afine" powder." The mobility and the dispersing properties of thepowdered product were equiv alent to those produced in Examples I and-II.

Efmmple. V

This example illustrates theme of at smaller. proportion of water" in preparing the products. of this invention and indicates the minimum-.1 limit; of waternecessary to obtain thorough distribu tion ofthe"chemica'ls -and'proper reaction be;- tweenthem':

450 parts" of'potatostarch' was placedin'v a. mixing-device suitable for mixingsubstantially dry materialsand" agitated; The starch used: in: this instance contained I3 '%moisture; As the". starch was agitated 4:5 1 parts of aluminumv sul fate dissolved inparts of water" was sprayedv into the." starch; After the aluminum sulfate: solution was thoroughly dispersed throughoutthe" starch, 5 Y parts of tri-sodium phosphate dissolved i'n 20 parts of water-was sprayed intogthe mixture and agitation continued until it also:

was uniformly dispersed" throughout the starch mixture; The resultantmixture of starch and chemicals wasthen dried-to about-12 moisture.- an'd groundto-ai fine powder. The mobility and the dispersing proper-ties of the powdered product'were superior to powdered redried starch but.- Wasinferior'in these qualities to the'products in- Examples I; IIan'd'IV. Theresults in-this ex ample" indicate that a. minimum of about l moisture .content is required in the starchand".

chemical mixture? to obtain satisfactory results;

Example; VI

This" example illustrates the effective. use of; other chemical combinations. than thoseldemonistratedin the previous examples To 450 parts ofpotato starch dispersed in 1000? parts of water was addedlOparts of aluminum. sulfate dissol'vedin40 parts of water. Themixture was agitated ten minutes and then: 5 parts 1 of soda ash dissolved in 40"part's'of waterwas added. The agitation was continued for about ten, minutes after which the bulk of the water was separated from the starch by filtration. The Qresultant damp starch product was then dried to? about 15% moisture content and ground to,

example v11 This example is another illustration of the -'effective use of chemical combinations other than those previously demonstrated. I

II To 450 parts of potato starch dispersed in 1000 parts of water was added6 parts of Epsom salts dissolvedinoo parts of water. The mixture was agitated for about 10 minutes then 6 grams of tri-sodiumphosphate dissolved in 50 parts of water was added. The agitation was continued for about '10 minutes after which the bulk of water was separated from the starch by filtration. The resultant damp starch product was then driedto about 15% moisture content andground to a fine powder. The powdered product obtained in this example was equivalent to those of EX- "'amples I, 'II; IV and VI in mobility and dispersing quality; The proportions of chemicalsused in this example are approximate and are based on thefollowing chemical equation:

Example VIII parts of Water was added parts of cupric sulfate I The . (anhydrous). dissolved in 100 parts water. mixturewas agitated for about 10 minutes then a 1% solution ofsodium hydroxide was slowly I added to bring the pH of the mixture to 7.0. Agitation was continued for another 10 minutes after which the bulk of the Water was separated from the. starch by filtration. The damp starch product'was,then,dried to about moisture content and ground to a fine powder. The powdered product of this example was a light blue in color I but was equivalent to the products of Examples I, II, IV, VI- and VII in mobility and dispersing quality..The proportions of chemicals used in this example are approximate and arebased on the following chemical equation:

-i;Because of the cupric hydroxide content the I dusting product of this experiment is effective as a fungicide. Greater or lesser proportions of I chemicals can be used to give a greater or lesser partswatr was added" 12 parts of calcium chloride dissolvedin 50. parts of water. The mixture was agitated ten minutes, then lO-parts of soda ash dissolvedin50 parts of water was added.

The agitation was continued for about 10 minutes after. whichrthe bulkuof the .waterwas separated by filtration. The resultant damp starch product was then redried to about 15% moisture content and ground "to a fine powder. The product obtained in this example had good mobility and dispersing properties but was not quite as good in thesequalities as Examples I, 11, IV, VI, VII and VIII. Iheproportionsof chemicals used in i the example are approximate and are based on the ch'emical equation: i

I CaCl2+NazCOr+CaC0zt+NaC1 I I i Example X This example illustrates the use of another chemical combination which is quite effective:

To 450 parts of potato starch dispersed in 1000 parts of water was added 14 parts zinc sulfate dissolved in 100 parts water. The mixture was agitated for about lO minutes then 4 parts of sodium hydroxide dissolved in 200 cc. of water was slowly added to the mixture. Agitation was continued about 10 minutes after which the bulk of the water was separated from the starch by filtration. The resultant damp starch product was then dried to about 15% moisture content and ground to a fine powder. The product of this example had good mobility and dispersing quality but was not as good in this respect as Examples I, 11, IV, VI, VII and VIII. The proportions of chemicals used in this example are approximate and are based on the chemical equation: I

This example also illustrates another chemical combination suitable for the practice of the invention: g

To 450 parts of potato starch dispersed in 1000 partsof water was added 6.5 parts of calcium chloride dissolved in 50 parts water. The mixture was agitated for about 10 minutes, then l parts of magnesium sulfate dissolved in 50 parts water was added. The agitation was continued for about 10 minutes after which the bulk; of the Water was removed by filtration. The resultant damp starch product was then dried to about I 15% moisture content and ground to afine powder. The product of this example had good mobility and dispersing quality, although it was .not as good in this respect as Examples I, II, IV,

VI, VII and VIII. The proportions of chemicals used in this example are approximate and are based-on an assumedreaction formula as follows:

Example XII II i 1 This example again demonstrates another sat v isfactory combination of chemicals:

which the bulkof the water was removed by filtration. The resultant-damp product was then ...:a nd.1 dispersion. properties. H

sag-emcee o dried. toabcutiifz moisture content .andxgronnd 1:; 't ellfine: powder. :2 The: product' of: itherzexample rhaclagood amobility .iandr dispersingnproperties.

'xThe; propdrt-ions of lch'emicals usediinizthisiexamammkpzexi HI "The; procedure followed. in" this example-rwas .1 the same as that followedirfExarnple ;;'exc ept that tapioca starch was'us'ed insteadi ofiiwheat Tistar'ch. 'i The resultant product was verysatisfac- .tory in regard'to'mobility and dispersing quality.

EacampZe XVIII I "The, procedure. followed in ,this. example was f'This example-illustrates another suitable 'COm- "th' Same asgthat followedinExam'pl xvhexcept pin'ation -of' chemicals:

' To 450 partsofpotato starch dispersed in 1-000 "parts"waiter was added'lopartsofbarium chloride dissolved in 60 parts of water. "The*mixture 1 was agitated---fowlOrminutesnthen17 parts of sodium sulfate dissolved in 60 parts of Water was added. The agitation was continued for 10 -..minutes-.after whichithe-bulk of thee watera'was removed by .ifiltration. The resultant udamp The proportions .of chemicals .used-inftheexample 1. are.- approximate. and are: 'basedon the-following Ihis example again demonstrates anothersuitu able combination of: chemicals:

"T 5450 parts of potato starch clispersedx in 1 000 parts-"of water was added 12=parts of :trieso'diu'm phosphate dissolved 60 parts: of water. "-The mixture was agitated tor minutes then-=5 parts calcium chloride dissolved in 40 partswatenwas added. The agitation was=continued'for .10;min-

antes.after.twhichethewbulk of the water was removed by filtration. The resultant dampwn product was then dried to moisture content ..and..ground-,-to. a fine. powder. Thelproduct of this... example was also satisfactory; fromnthe standpoint of mobility and dispersability. The =.pnoportions of chemicals. used in thisexample are. approximate. and 1: are based on. rthe ifollowing chemical equation:

..',..'Ewmnple .X V

:iThis: example 1 illustrates the: =use of #Wheat starch in: making the product" of the'dnverition:

To 4'50 pa'rts'rofv wheat 'starch 'dispersed' in 1-000 that arrow r'o'otstarch was used instead of wheat starch. The resultant dustingproduct was .very

vs'atisfactory. in zmobility and dispersing properties.

The above examples 'iliustr'ate only a few of the armany different combinations of ::chemicalsf; that .1: maybe; .used: sin. 'thep-practiceriofi this. invention.

This will be apparent?touthosewwhoiare familiar =.=.-with. athe chemical art. ItigiS intended that these 1iexamples demonstrate -the fact. that; any two: or gmorewchemicals whichin solution";reactqtoiform an. insolublev precipitate are 3effective. ins accom- ,-p1ishing s'the purposes of the -"-invention.

-This: example demonstrates adifferent: procetime than the; preceding examples-.i'inrthat' ithe lreaction" of.-the.-chemicalszto .form. the: precipitate; does not .take :place ,inrthe-presence; 10f. Ithe .istarch:

, 1 To-- 9 parts of r aluminum a sulfate dissolved in e100; parts of water was: added 10; parts :ofzrtriasodium' phosphate'dissolved in [100 parts of. water. The resultantaqueous suspension of 'theprecipitated reaction product was. then, added .to .450 parts of potato starch iiisp'ersedgirr' 'IOOOpaYtS'pf water. The mixture was' then agitated thoroughly for about 10. minutes after which the bulk of the water was removed by filtration. The resultant' damp starchproduct wasthen dried to '==-'ab.out- 1Z5 *-moisture content and ground-rte: a fine powder. The powdered productof thls='example had very good" mobility and dispersing properties. 7

T In-itreating a starchwith this-method"btpro- :cedure rit is desirable -that the precipitated-maiaterialt'abe freshly precipitated. In' other -words, iitrsshould :not be allowed to? age too 'longia before J:...adding. it .to the starch. If the precipitated-ama- :tends .toaa'gglomerate andccannot be rea'dilyidisipersedzfto .it-S originalx smallapartielef:form: when @mixed: withithe starch.

.eAlthough 1: in: the: examples giverr therproporsulfate dissolved in 40 parts 'ofiwater. The-mixture was: agitated for 10 -minutes; then. 10 parts .'of::trisodium phosphate dissolved in 40- parts waterwas added. "The agitation was continued ;:.:bining,.chemically equivalent proportions, an ex- .rzicesstof ;either:=-of;the chemicals-may 'generallyz'be abused without a detrimentat effect on' ithe-ifinal product. The exceptions-t0..thisrstatement, how- 'for aboutlO minutes after which the'bullrof the. to ever, would be suchinstancesof unbalance t t water was removed.from the-starch=by,=.filtration. .The resultant damp product was then dried to about 15% moisture content and ground to a fine powder. The product-bfthis experiment compared: favorablyito .those .of the previous examples. .65

both in mobility.andadispersingwquality. .{The ,-..chemicals-used insthis example are .thesame as .rusedinExample I. I

ErampZa XVI The procedure. followed. in. thisiexampletwas lthesame. as-thatfo-llowed inEx-ampleXV, except flthati corn ..starch was ...used. instead of wheat .starch. I The .resultantproducthad goodmobility 1 though the minimum required amount of chem- -,icals =,-.will .varysomewhat with ;.difierent;1chemi- .lcfal ,conrbinations; it; may be stated generally. that at least 1 part of the precipitated-reactionprodtuct .is required.fon-6800partsv of: starch. These i'ldQPlOPDBtiQhs. arewbasedi' :onr dry weightstestimated from proportions'of chemicals used in Example III Example V shows the minimum of water that may be used in the starch and chemical combination in order to obtain satisfactory reaction between the chemicals. This also will vary somewhat with different combinations, but in general it may be stated that at least 25% moisture content is required in the starch and chemical combination. i I i There is no definite upper limit on the proportions of chemicals or water except practical considerations. The examples demonstrate. good practice in pursuing the teachings of the invention. As a practical matter, there is no point in employing an excess of the precipitate forming reagents where a smaller quantity will produce the optimum effect unless the precipitate also has functions apart from its function in increasing the mobility and dispersability of the starch. Thus, in Example VIII, the precipitated material. being a copper salt, functions as, a fungicide. In some cases, the physical nature of the precipitate will limit the quantity used to a maximum around by weight of the starch. i

The products of the present invention, although containing in many instances more moisture than the original starches, retain their mobility and free flowing properties under ordinary atmospheric conditions, even at relatively high humidities. from 10% to 30% by weight of moisture in the final product. The amount of moisture therein may be varied depending upon the use of the product, Where the, product is employed in printing or in the graphic arts field, the optimum moisture content is -20% by weight. The products containing relatively large amounts of moisture have the advantage of more rapidsettling in the atmosphere.

The temperature at which the precipitation is The preferred products contain effected may vary widely from a minimum above the freezing point of the liquid used as the reaction medium to a maximum below the gelatinization temperature of the starch. Excellent results have been obtained at temperatures of to80F.

Examples IV and V demonstrate the practice of the invention wherein for practical reasons it is desired to use a minimum amount of water in preparing the product, such as in cases where filtration equipment is not available. The other examples, however, illustrate the preferred practice if the product is made in the starch manufacturing' plant.

Examples XV, XVI, XVII and XVIII demonfor such purposes where a larger grain size is dsirable.

The precipitation reaction product is preferably formed in situ in the presence of thestarch either by addingone reagent to the starch followed by a precipitant or by adding both reagents simultaneously. It is preferred, however. to allow the starch to absorb an aqueous solution of" one reagent before adding the second reagent to bring about the doubledecomposi tion which results in the formation of the precipitate. Although the invention is not limited to anytheory, the results obtained may be due in part at least to the penetration of the'precipitate forming chemicals into the envelope of the starch granule.

Especially good results have been obtained by coating the starch granules with freshly precipitated water insoluble salts and hydroxides of aluminum, magnesium, copper and silicon, .e;

aluminum phosphate, aluminum hydroxide,

magnesium posphate, cupric hydroxide and .silicic acid.

The term mobile is used herein to describe the free flowing characteristic of the powdered starch granules which distinguishes them from ordinary starches that tend to cake or agglomerate.

Substantial amounts of other powdered material may be blended with the dusting product of this invention without serious detriment to its mobility and dispersing :quality. It is useful as a base material to carry fungicides,insecti cides, and medicaments. I

It has been found that the products of the invention (e. g., the product'of Example I are especially suitable for preventing oiT-set in printing processes. In one such process where a powdered material is fed from a hopper by means of a roll and dischargesadjacent an electronic tube, the products of the present invention discharge more readily and in a more highly dispersed form than ordinary starches. chanical devices in which the dusting powder-is discharged by other means, suchfas air bla'st spraying or sifting methods, likewise give good results withthe products of the invention.

The invention is hereby claimed as follows:

1. The method of forming a mobile powdered composition which comprises essentially intimately mixing and coating starch granules in the presence of moisture with a finely divided freshly precipitated Water insolublesolidof smaller particle size than the starch granulesand dryingtheresultant coated 'granles, said finely divided water insoluble solid being from the group consisting of freshly precipitated water insoluble inorganic salts and hydroxides.

2. The method of forming a mobile powdered composition which comprises essentially intimately mixing and coating starch granules in the presence of at least 25% by weight of moisture, calculated on the weight of the starch, with a finely divided freshly precipitated water insoluble solid of smaller particle size than the .in situ by double decomposition to form a finely divided water insoluble solid precipitate of smaller particle size than the starch granules and drying the resultant product, said finely divided water insoluble solid being from the group consisting of freshly precipitated water insoluble inorganic salts and hydroxides.

4. The method of forming a mobile powdered composition comprising intimately dispersing a Other I me starchinrwateitswith a plurality iota-Water soluble-7:7; removing-i moisture".tfromlvthe,; .-resultantf;product:: inorganic.compounds:whichrreactimsitu'byrdoue: until a mobile product is obtained.

ble. decomposition to; formwa finelydivided" ill/3.11813 9."?Anmethod .tofirforming."ac-mobile powdered insoluble iSOlid precipitatetr.of:ismallergxparticle?a compositiorrnwhich; comprises: essentially.v in; size :thanythe pstarchu'igranules's"ands drying; the::. 5 timately dispersing. :a fstarchtin r-water; adding; resultant :product,saidcfinely. dividedxwvater inea cuprics sulfate and r.sodium hydroxide" .inv an? soluble solid being; from nthe..:1;gr0uprsxconsisting.F amount sufiicientz to formroa -finely divi'deti'pre-i of freshly precipitated water insolubleitinorganictz cipitateiwhi'ch coats .ithe starch granule's'i and r.

salts. and hydroxides-iv. removing .-moisture :from' the resultant. product '5.-The method of forming a mobilezpowdereds oz{until a mobile product is obtained. composition comprising 1 intimately :zdispersing; :a 10.1. A 6 method "offorming a -mobile powdered starch in iwaterwith'a rpluralitysof:.watensolubler composition: which: comprises essentially. in'='- compounds which.=;rea.ct intsituaby doubletdees timately dispersing a:starchinnwatery'adding composition to::form;a;fine1yi:divioled watelfiiinii' aluminum sulfate t. and :sodium carbonate in ian: soluble solid precipitate of smaller particlezsizendocamount sufficienta'to form a finely -divided prethanthe starch granules 'and edrying thezresultcipitatei: i-whichficoats .the 'starch 'granules, and

ant .product, .the. quantitmvof::saidxzprecipitate.r removing moisturervfrom the resultant product correspondingto.atleastonezpart'per:680,0 parts; until a mobileFproduct .is obtainedzr by.weight of. starch,psaid:firiely ;divided:'wvatem 11:Afimethodof-forming a mobilevpowde'red" insoluble solid being from the group consisting'.:-i20 jcomposition which comprises. essentiallysvimn of freshlycprecipitated waterainsolublelsinorganic tim'ately" dispersing. 7a starch in water; adding salts: and hydroxides; so'dium-lrsilic'ate ond-hydrochloric acid in :ar'r: 6. The. method-rofziormingga mobileapowdeitedo amountxsufficient'xto form a fin'ely divided pre=- composition: comprising.rintimately.:dispersing?v a Ti cipitate'i which coatsibith'' Starch? granules; and potato starchiinzwaterxwithea plurality oizwatenc25 removing moisture frbmihfiesultflht' p u soluble compounds which .reactvinasitux byxdoublelz: until"v a :mobile. product :is: obtained. 7 decomposition'tdform afinely driridedz .water in- GEORGE. KRIS'ANZ soluble solid.:.precipitatelaoitzsmallen parti'cleissizezi than-the starch :granulesrand.:dryingthe oesulta- REFERENCESTEICITED ant. product:said.finely. ;divided cwater:zinsolu-b'lei30"'- The following references are of're'cord ,inqthe solid ein fr0m- --eroup consistingpfsireshly fil e ofthis patenty watenin'soluble. unorgamc: saltsnzando UNITED STATESMPATENTS 7.;A. methodn' of forming: a ;mobile.=;-.-:powdemdao Number am e A composition which.-- .comprisess=essentially inti+-35g ,432Af10 Burme1ste'rr=; Oct. 17,1 2 mately-;disp ersing; .ar;starch .;in;z;watery; adding-if; V FOREIGN PATENTS; aluminum sulfate..anditrisodiumphosphate.imanb U amount suflicient'to.formtrazfinelwdiilidedzaSpre Nunbern" Date" cipitate which coats the starch-granules;ancmeiv 25:55 swltzfifland """""'j"'" 2i moving-moisture from thezresultantzproduct until 40 Austna T'T"' 2 a mobile product. isobtainedz. GreatBntam 1939 8. A method. of -forming. -;a -m'obi'le --po.wdered OTHEHREFERENCES cmpsltln r Whlch comm essentlau'y' Poucher: SPerfumes. o Soaps-. (1929-) VOl'gilhi.

timately dispersing 1a starch in-I-water,- adding-;- pgs 4827483) magnesium sulfate and .:trisodiumphosphate in'45 t." 1 J; an. amount sufficient to-oform a finely divided 2' ig gsg ggi Hand "Bock by Perry precipitatewhich-coatsrthe-starch.granules andm I 

1. THE METHOD OF FORMING A MOBILE POWDERED COMPOSITION WHICH COMPRISES ESSENTIALLY INTIMATELY MIXING AND COATING STARCH GRANULES IN THE PRESENCE OF MOISTURE WITH A FINELY DIVIDED FRESHLY PRECIPITATED WATER INSOLUBLE SOLID OF SMALLER PARTICLE SIZE THAN THE STARCH GRANULES AND DRYING THE RESULTANT, COATED GRANLES, SAID FINELY DIVIDED WATER INSOLUBLE SOLID BEING FROM THE GROUP CONSISTING OF FRESHLY PRECIPITATED WATER INSOLUBLE INORGANIC SALTS AND HYDROXIDES. 